1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a reflection type LCD device in which light efficiency reflection is improved by a hologram layer.
2. Description of the Related Art
LCD devices have advantages in terms of low power consumption due to a low driving voltage and a simplified structure. Most LCD devices which are currently being used adopt a TN (twisted nematic) type liquid crystal or an STN (super twisted nematic) type liquid crystal. Accordingly, at least one polarizer is necessary provided in order to control light, with, a filter is to realize full color image. A reflection layer is further provided for a reflection type LCD device.
FIG. 1 is a sectional view illustrating a general reflection type LCD device having the color filter and the reflection layer.
Referring to the drawing, the reflection type color LCD device is comprised of an upper substrate 12 and a lower substrate 26, an upper polarizer 10 disposed on the upper substrate 12, a lower polarizer 28 which can be selectively disposed below the lower substrate 26, and a reflection layer 30 disposed below the lower polarizer 28. A color filer 14 is arranged to be below the upper substrate 12. A plurality of upper electrodes 16 are formed in strips below the color filer 14 and a plurality of lower electrodes 24 are formed in strips on the lower substrate 26. The upper and lower electrodes 16 and 24 are arranged to cross with one another and covered with upper and lower orientation films 18 and 22, respectively. An LCD layer 20 is formed between the upper and lower orientation films 18 and 22.
In the above-mentioned reflection type color LCD device, input light is partially blocked by the color filter and the upper and lower polarizers 10 and 28 disposed midway in an optical path of the light. In particular, since over 50% of the light inputted to the LCD device is blocked by the polarizers, the amount of light which can be reflected by the reflection layer 30 is reduced. Therefore, to improve brightness of an image in the reflection type LCD device, the efficiency of light use should be increased.